Root insert and a wind turbine having wind turbine blades with root inserts

Abstract

A wind turbine is presented. The wind turbine includes a tower, a rotor coupled to the tower, and a plurality of blades coupled to the rotor, wherein each of the plurality of blades comprises a root and a plurality of root inserts positioned circumferentially along the root. Each of the root inserts includes a metal bushing including an outer surface and a plurality of grooves formed at least on the outer surface, a core coupled to the metal bushing, and a plurality of layers wrapped around the metal bushing and the core, wherein a layer of the plurality of layers comprises a different fiber orientation from a fiber orientation of another layer of the plurality of layers.

The invention claimed is: 
     
       1. A wind turbine comprising:
 a tower; 
 a rotor coupled to the tower; and 
 a plurality of blades coupled to the rotor, wherein each of the plurality of blades comprises a root and a plurality of root inserts positioned circumferentially along the root, wherein each of the root inserts comprises:
 a metal bushing comprising an outer surface and a plurality of grooves formed at least on the outer surface, the plurality of grooves comprising parallel grooves having a helical or perpendicular orientation with respect to a longitudinal axis of the metal bushing; 
 a core coupled to the metal bushing; 
 a plurality of layers wrapped around the metal bushing and the core, 
 
 wherein a layer of the plurality of layers comprises a different fiber orientation from a fiber orientation of another layer of the plurality of layers;
 wherein the plurality of layers comprises:
 a first layer in physical contact with the metal bushing and the core, the first layer comprising a first fiber orientation non-parallel to the orientation of the grooves so as to cross over the grooves; 
 a second layer wrapped around and in physical contact with the first layer, the second layer comprising a second fiber orientation non-parallel to the first fiber orientation; and 
 wherein the first layer occupies the plurality of grooves due to the second fiber orientation of the second layer around the first layer and a force applied by the wrapping of the second layer on the first layer. 
 
 
 
     
     
       2. The wind turbine of  claim 1 , wherein the first layer comprises the first fiber orientation at an angle in a range greater than 0 degrees in magnitude and less than ±90 degrees with respect to the longitudinal axis of the metal bushing and wherein the second layer comprises the second fiber orientation at an angle of about ±90 degrees with respect to the longitudinal axis of the metal bushing; or the first fiber orientation comprises the angle of about ±90 degrees with respect to the longitudinal axis of the metal bushing, and the second fiber orientation comprises a range greater than 0 degrees in magnitude and less than ±90 degrees with respect to the longitudinal axis of the metal bushing. 
     
     
       3. The wind turbine of  claim 1 , wherein the plurality of layers further comprises a third layer wrapped around and in physical contact with the first layer and the second layer. 
     
     
       4. The wind turbine of  claim 3 , wherein the third layer comprises a third fiber orientation at an angle between 0 degrees to ±90 degrees with respect to the longitudinal axis of the metal bushing. 
     
     
       5. The wind turbine of  claim 4 , wherein the third fiber orientation of the third layer is same as the first fiber orientation of the first layer. 
     
     
       6. The wind turbine of  claim 4 , wherein the third fiber orientation of the third layer is different from the first fiber orientation of the first layer. 
     
     
       7. The wind turbine of  claim 3 , further comprising:
 a cover surrounding the first layer, the second layer, and the third layer. 
 
     
     
       8. The wind turbine of  claim 1 , wherein the outer surface of the metal bushing comprises a flat surface and a grooved surface comprising the plurality of grooves. 
     
     
       9. The wind turbine of  claim 8 , wherein the second layer is wrapped around a portion of the first layer that covers the grooved surface. 
     
     
       10. The wind turbine of  claim 1 , wherein at least one of the plurality of layers comprises at least one of glass fiber rovings, carbon rovings, aramid rovings, glass fibers, pre-impregnated rovings, wet rovings, dry rovings, hybrid rovings, and rovings with a binder material. 
     
     
       11. The wind turbine of  claim 10 , wherein the plurality of layers comprises carbon rovings wrapped around flat surfaces of the metal bushing, and wrappings of glass rovings occupying the plurality of grooves of the metal bushing. 
     
     
       12. The wind turbine of  claim 1 , wherein the plurality of layers comprises a plurality of rovings made of same material. 
     
     
       13. The wind turbine of  claim 1 , wherein a material of a roving of one of the plurality of layers is different from a material of other layers of the plurality of layers. 
     
     
       14. The wind turbine of  claim 1 , wherein one of the plurality of layers comprises a first roving and a second roving, wherein the first roving comprises a first material and the second roving comprises a second material different from the first material. 
     
     
       15. A root insert comprising:
 a metal bushing comprising an outer surface and a plurality of grooves formed at least on the outer surface, the plurality of grooves comprising parallel grooves having a helical or perpendicular orientation with respect to a longitudinal axis of the metal bushing; 
 a core coupled to the metal bushing; and 
 a plurality of layers wrapped around the metal bushing and the core, 
 wherein a layer of the plurality of layers comprises a different fiber orientation from a fiber orientation of another layer of the plurality of layers; 
 wherein the plurality of layers comprises:
 a first layer in physical contact with the metal bushing and the core, the first layer comprising a first fiber orientation non-parallel to the orientation of the grooves so as to cross over the grooves; 
 a second layer wrapped around and in physical contact with the first layer, the second layer comprising a second fiber orientation non-parallel to the first fiber orientation; and 
 wherein the first layer occupies the plurality of grooves due to the second fiber orientation of the second layer around the first layer and a force applied by the wrapping of the second layer on the first layer. 
 
 
     
     
       16. The root insert of  claim 15 ,
 wherein the first layer comprises the first fiber orientation at an angle in a range greater than 0 degrees in magnitude and less than ±90 degrees with respect to the longitudinal axis of the metal bushing and wherein the second layer comprises the second fiber orientation at an angle of about ±90 degrees with respect to the longitudinal axis of the metal bushing; or the first fiber orientation comprises the angle of about ±90 degrees with respect to the longitudinal axis of the metal bushing, and the second fiber orientation comprises a range greater than 0 degrees in magnitude and less than ±90 degrees with respect to the longitudinal axis of the metal bushing.